What factors determine the size of a propeller?

The size of a propeller is determined primarily by its pitch and diameter.

Pitch refers to the distance a propeller would move forward in one complete revolution if it were moving through a solid medium, similar to how a screw threads through wood. A propeller with a higher pitch will move a boat farther with each revolution, which can result in higher speeds but may require more power to turn.

Diameter, on the other hand, is the overall width of the propeller from tip to tip. A larger diameter generally increases the thrust produced by the propeller, which can be crucial for larger vessels or those that need to carry heavy loads.

These two parameters are critical in determining how effectively a propeller can convert engine power into forward motion, influencing the overall performance and efficiency of the vessel. Other factors, like the engine’s horsepower and the boat's design and intended use, also play significant roles in propeller selection, but pitch and diameter are the foundational aspects directly related to the propeller's size.